<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<div id="app">
    <h2>当前计数：{{counter}}</h2>
    <button v-on:click="add">+</button>
    <button v-on:click="sub">-</button>
</div>
</body>
<script src="../../vue.js"></script>
<script>
    const app = new Vue({
        el: '#app',
        data: {
            counter: 0
        },
        methods: {
            add() {
                this.counter++
            },
            sub() {
                this.counter--
            }
        }
    })
</script>
</html>
